Previous studies have shown that mean corpuscular volume (MCV) levels are associated with the prognosis of patients with cardiovascular disease. However, the relationship between MCV levels and mortality in patients with intracerebral hemorrhage (ICH) remains unclear. Patients with ICH were extracted from the Medical Information Mart for Intensive Care-III database. The primary outcome measure was 30-day mortality. Multivariate Cox regression analysis was used to investigate the relationship between MCV at admission and 30-day mortality in ICH patients. We enrolled 1100 patients with ICH. After adjustment for potential confounders, we found that a 1 unit increase in MCV (fl) was associated with a 3% increase in 30-day mortality (HR = 1.03, 95% CI = 1.01-1.05, P = .0015). High MCV (MCV >= 92 fl) compared with the low MCV group (MCV < 87 fl) showed a 46% increase of 30-day mortality (HR = 1.46, 95% CI = 1.10-1.92 P = .008). In subgroups analysis's the results remained stable. We demonstrated that MCV at admission was positively associated with 30-day mortality. The Kaplan-Meier (KM) method was used to plot survival curves of three groups with different admission MCV levels.